Search results for "VIOLATION"
showing 10 items of 540 documents
Amplitude analysis ofB0→D¯0K+π−decays
2015
The Dalitz plot distribution of B-0 -> (D) over bar K-0(+)pi(-) decays is studied using a data sample corresponding to 3.0 fb(-1) of pp collision data recorded by the LHCb experiment during 2011 and 2012. The data are described by an amplitude model that contains contributions from intermediate K* (892)(0), K*(1410)(0), K-2*(1430)(0) and D-2(*)(2460)(-) resonances. The model also contains components to describe broad structures, including the K-0(*)(1430)(0) and D-0(*)(2400)(-) resonances, in the K pi S-wave and the D pi S-and P-waves. The masses and widths of the D-0*(2400)(-) and D-2(*)(2460)(-) resonances are measured, as are the complex amplitudes and fit fractions for all components in…
A combined beta-beam and electron capture neutrino experiment
2009
The next generation of long baseline neutrino experiments will aim at determining the value of the unknown mixing angle, theta_{13}, the type of neutrino mass hierarchy and the presence of CP-violation in the lepton sector. Beta-beams and electron capture experiments have been studied as viable candidates for long baseline experiments. They use a very clean electron neutrino beam from the beta-decays or electron capture decays of boosted ions. In the present article we consider an hybrid setup which combines a beta-beam with an electron capture beam by using boosted Ytterbium ions. We study the sensitivity to the CP-violating phase delta and the theta_{13} angle, the CP-discovery potential …
Observation of directCPviolation in the measurement of the Cabibbo-Kobayashi-Maskawa angleγwithB±→D(*)K(*)±decays
2013
We report the determination of the Cabibbo-Kobayashi-Maskawa CP-violating angle γ through the combination of various measurements involving B^± → DK^±, B^± → D^*K^±, and B^± → DK^(*±) decays performed by the BABAR experiment at the PEP-II e^+e^- collider at SLAC National Accelerator Laboratory. Using up to 474 million BB pairs, we obtain γ=(69_(-16)^(+17))° modulo 180°. The total uncertainty is dominated by the statistical component, with the experimental and amplitude-model systematic uncertainties amounting to ±4°. The corresponding two-standard-deviation region is 41° < γ < 102°. This result is inconsistent with γ=0 with a significance of 5.9 standard deviations.
CP observables with spin-spin correlations in chargino production
2008
We study the CP-violating terms of the spin-spin correlations in chargino production e+e- -> chi^+/-_1 chi^-/+_2, and their subsequent two-body decays into sneutrinos plus leptons. We propose novel CP-sensitive observables with the help of T-odd products of the spin-spin terms. These terms depend on the polarizations of both charginos, with one polarization perpendicular to the production plane. We identify two classes of CP-sensitive observables; one requires the reconstruction of the production plane, the other not. Our framework is the Minimal Supersymmetric Standard Model with complex parameters.
Search forCPviolation in neutralDmeson Cabibbo-suppressed three-body decays
2008
Using 385fb-1 of e+e- collision data collected at center-of-mass energies around 10.6 GeV, we search for time-integrated CP violation in the Cabibbo-suppressed decays D0/D0→π-π+π0 and D0/D0→K-K+π0 with both model-independent and model-dependent methods. Measurements of the asymmetries in amplitudes of flavor states and CP eigenstates provide constraints on theories beyond the standard model, some of which predict CP violation in amplitudes at the 1% level or higher. We find no evidence of CP violation and hence no conflict with the standard model. © 2008 The American Physical Society.
Search forCPviolation in the decayτ−→π−Ks0(≥Oπ0)ντ
2012
We report a search for CP violation in the decay \tau- -> \pi - \K^0_S (>= 0 \pi 0) \nu_\tau\ using a dataset of 437 million \tau\ lepton pairs, corresponding to an integrated luminosity of 476 fb^{-1}, collected with the BABAR detector at the PEP-II asymmetric energy e+e- storage rings. The CP-violating decay-rate asymmetry is determined to be (-0.45 +/- 0.24 +/- 0.11)%, approximately three standard deviations from the Standard Model prediction of (0.33 +/- 0.01)%.
Measurement of the time-dependentCP-violating asymmetry inB0→KS0π0γdecays
2005
We present a measurement of the time-dependent CP-violating asymmetry in B{sup 0} {yields} K*{sup 0}{gamma} decays with K*{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0} based on 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. In a sample containing 157 {+-} 16 signal decays, we measure S{sub K*{sup 0}{gamma}} = -0.21 {+-} 0.40 {+-} 0.05 and C{sub K*{sup 0}{gamma}} = -0.40 {+-} 0.23 {+-} 0.03, where the first error is statistical and the second systematic. We also explore B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0}{gamma} decays with 1.1 < m{sub K{sub S}{sup 0}{pi}{sup 0}} < 1.8 GeV/c{sup 2}…
Measurements of directCPasymmetries inB→Xsγdecays using sum of exclusive decays
2014
We measure the direct CP violation asymmetry, A_(CP), in B→X_sγ and the isospin difference of the asymmetry, ΔA_(CP), using 429 fb^(−1) of data collected at Υ(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy e^+e^− storage rings operating at the SLAC National Accelerator Laboratory. B mesons are reconstructed from ten charged B final states and six neutral B final states. We find A_(CP)=+(1.7±1.9±1.0)%, which is in agreement with the Standard Model prediction and provides an improvement on the world average. Moreover, we report the first measurement of the difference between A_(CP) for charged and neutral decay modes, ΔA_(CP)=+(5.0±3.9±1.5)%. Using the value of ΔA_(CP)…
CPT and CP, an entangled couple
2020
Even though it is undoubtedly very appealing to interpret the latest T2K results as evidence of CP violation, this claim assumes CPT conservation in the neutrino sector to an extent that has not been tested yet. As we will show, T2K results are not robust against a CPT-violating explanation. On the contrary, a CPT-violating CP-conserving scenario is in perfect agreement with current neutrino oscillation data. Therefore, to elucidate whether T2K results imply CP or CPT violation is of utter importance. We show that, even after combining with data from NO$\nu$A and from reactor experiments, no claims about CP violation can be made. Finally, we update the bounds on CPT violation in the neutrin…
Cornering the revamped BMV model with neutrino oscillation data
2017
Using the latest global determination of neutrino oscillation parameters from~\cite{deSalas:2017kay} we examine the status of the simplest revamped version of the BMV (Babu-Ma-Valle) model, proposed in~\cite{Morisi:2013qna}. The model predicts a striking correlation between the "poorly determined" atmospheric angle $\theta_{23}$ and CP phase $\delta_{CP}$, leading to either maximal CP violation or none, depending on the preferred $\theta_{23}$ octants. We determine the allowed BMV parameter regions and compare with the general three-neutrino oscillation scenario. We show that in the BMV model the higher octant is possible only at $99\%$ C.L., a stronger rejection than found in the general c…